The USDA best describes the etymology of the name screwworm: ...

Maggot therapy is a wound healing technique in which healthcare professionals apply medical grade maggots to dead or infected tissue to keep the wound clean. It is also known as larval therapy.

Jack Pocock reported feeling sick and throwing up when he spotted the larva in his lamb doner, which he had already started eating, after purchasing it at the Gabalfa Fish Bar in Cardiff.